linux-user: Emulate /proc/cpuinfo for Alpha

linux-user: Emulate /proc/cpuinfo for Alpha

Add emulation for /proc/cpuinfo for the alpha architecture.

alpha output example:

(alpha-chroot)root@p100:/# cat /proc/cpuinfo
cpu                     : Alpha
cpu model               : ev67
cpu variation           : 0
cpu revision            : 0
cpu serial number       : JA00000000
system type             : QEMU
system variation        : QEMU_v8.0.92
system revision         : 0
system serial number    : AY00000000
cycle frequency [Hz]    : 250000000
timer frequency [Hz]    : 250.00
page size [bytes]       : 8192
phys. address bits      : 44
max. addr. space #      : 255
BogoMIPS                : 2500.00
platform string         : AlphaServer QEMU user-mode VM
cpus detected           : 8
cpus active             : 4
cpu active mask         : 0000000000000095
L1 Icache               : n/a
L1 Dcache               : n/a
L2 cache                : n/a
L3 cache                : n/a

Signed-off-by: Helge Deller <deller@gmx.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230803214450.647040-4-deller@gmx.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>